Lowbrow humor and cheesy music executed properly in a simple + fun self-parodying FPS? Count me in!
You're Lo Wang, the guy who sang "The Lo Wang Rap." Wielding two uzis and hurling sticky bombs, you fight ninjas and koi. Whenever you see a 2D anime-girl sprite, you say something sexist and/or racist. You nuke enemies that look like Baraka from MKII while cheesy Tallarico synth plays over everything. That's basically it, but it's way more fun than I make it sound - think about it. You fight fish with shurikens, you make lowbrow jokes whenever you can ("Who wants some Wang?"), and for a game that went under the radar, it was pretty revolutionary. You could swim, operate vehicles and machinery, fight through very large and interactive maps filled with a variety of cool backgrounds and even some puzzles, build your own levels in the Build editor, and there were MANY easter eggs in Shadow Warrior. Some of them you could see if you used cheat codes - the game encouraged you to do whatever you had to do in order to have some fun and that's something newer games lack: The encouraging people to try new things. And if you wanted a challenge, play the game on a higher difficulty without the codes like you would any other. The hardest difficulties definitely gave you a challenge to say the least. The deathmatch arenas were also quite, quite fun, and there was a level in which the floor was programmed to serve as a racetrack much like the speed level in We Love Katamari. Just stand on the "track" and fire at people, jumping to shortcuts and opening secret passages... And this was in 1997!
Yes, '97 and I still play this game. And I know many who still do. The graphics are definitely outdated but if you don't care about that sort of thing and it won't get in the way of your enjoying really fast-paced and fun gameplay, find this game and install it immediately. Even if it's just for the humor, it's definitely an obscure game to play and enjoy. Not the best PC FPS I can think of, but definitely up there on my top 3. Simply put, you want something to pick up really quick and just have fun, launching missiles at purple jumpsuit-wearing ninjas? You know where to go.